If it's wide enough, do wide slalom turns to cut your speed. If you find you're going faster than you feel comfortable with you can just turn uphill instead of down. Heel brake is fine if used correctly, and you can reduce your speed with the t-stop if that's working well and the hill isn't too steep. When I'm planning on tackling a route with a hill that scares me I start at the bottom, go up a little way, turn, and come down using one of the methods above. Then I go a little higher, repeat, and so forth, until I can do the whole hill. Hills generally scare me ****less but I've surprised myself by what I can manage, by tackling them from the bottom up to start with.

An 8% grade will push you past 30mph in a hurry. Unless the 8% part is just a small bump or you don't actually need to stop in a reasonable distance, I think you will need some rather advanced methods.